Abrasive apparatus



Oct. 3, 1933. 'w. STEVER v 1,928,800-

ABRASIVE APPARATUS Filed June 14. 1929 2 Sheets-Sheet 1 IN VEN TOR.

24/171547 5 Za z/er A TTORNEYJ "0a. 3, 1933. w. STEVER 1,928,800

ABRASIVB APPARATUS Filed June 14, 19 29 2 Sheets-Sheet 2 Yl/ZZZz'am Sim/er INVENTOR. v

A TTORNEYS.

Patented Oct. 3, 1933 UNITED STATES PATENT OFFICE ABRASIVE APPARATUS ration of Ohio Application June 14,1929. Serial No. 370,904

1 Claim. (Cl. 51-197) The present invention, relating, as indicated, to abrasive apparatus, is particularly directed to a new and improved supporting pad for an abrasive disk employed in the now common types of portable abrasive or surfacing machines. These machines, which are in common use for the surfacing of panels, etc., consist of a casing provided with handles for the operator and containing either an electrical or pneumatic motor or driving gears which receive power from a flexible shaft. The casing also supports an extending shaft, on which is mounted, first, a yieldable pad of some construction, and then against the outer surface of the pad, an abrasive disk, the pad and disk being secured to the shaft at their respective centers and being ordinarily otherwise free from each other.

These machines have gone into very extensive use and are employed with various sizes of abrasive disks, such as 9", 7", 5", etc. with various individual pads of the proper size supporting each size of disk. As the disks are applied to the work at their outer surfaces, this is the part which first wears away and the disks are then sometimes cut down to the next size and must then of course be used with a different size of supporting pad.

The object of the present invention is the provision of a yieldable supporting pad constructed to permit of work with the edge of the abrasive disk and formed of separable units to allow the same pad to be successively used with various sizes of disks upon removal of one or more of the separable parts of this supporting element. A further object of the invention is the provision of a simple and very inexpensive pad of this type suitable for certain types of work and permitting both use of the disk on its flat portion and also at its edge to surface concave surfaces, such for example as those which occur between a metal panel and a superimposed molding strip.

To the accomplishment of the foregoing and related ends, said invention, then, consists of the means hereinafter fully described and particularly pointed out in the claim; the annexed drawings and the following description setting forth in detail certain structure embodying the invention, such disclosed means constituting, however, but one of various forms in which the principle of the invention may be used.

In said annexed drawings:-

Fig. 1 is a plan view of my improved pad and supporting hub therefor; Fig. 2 is a transverse section on the plane 22, Fig. 1; Fig. 3 is a bottom plan view of the hub; Fig. 4 is a section v as vulcanized fiber.

on the line 44, Fig. 3; Fig. 5 is a plan view of the largest of the separable elements of the pad; Fig. 6 is a view similar to Fig. 2, but showing the pad with its largest element removed; and Fig. 7 is a transverse sectional view showing the pad and disk supported thereby in use against a concave surface.

Referring now to Figs. 1 and 4, inclusive, there is shown a hub 1 provided with a central threaded opening 2 adapted to be engaged upon a corresponding threaded end of the supporting shaft of a portable machine such as I have described. This hub 1 is provided with a central locating projection 4 and with two oppositely directed engaging wings 5, each of which consists of a v portion 6 which extends angularly from the lower face of the hub 1 and a second portion 7 which extends almost parallel with the surface of the hub 1. The central locating projection 4 and the wings 5 serve to engage and hold in proper registration the separable elements which comprise my improved supporting pad and also the abrasive disk supported thereby.

The separable elements of my pad consists of disks 1o, 11 and 12 shown in Fig. 2, which may be formed of some tough resistant material, such Each of these disks is of some thickness and is provided at a central portion with a central opening 13 and connecting slots 14 and 15. The opening 13 engages over 35 the locating projection 4 on the hub and the slots 14 and 15 engage over the portions lot the wings 5 and are then brought into engagement with the portion 6 of these same wings by being iven a slight rotational movement about the hub. An abrasive disk 20, provided with a similar central opening and connecting slots, is then similarly engaged over the projection 4 and the rings 5 and is rotated in a snug frictional engagement beneath the lower tapered surfaces of the portions 6 and 'Iof thewings 5.

When it is desired to use a disk of smaller size the large disk 20 is removed by being turned in a direction to cause the slots to ride up over the wings 5, after which the larger element 10 is similarly removed. A disk of the same size as the second of the supporting elements 11 is then applied in the same manner as before.

If a disk of the smallest size is to be used, then both the elements 10 and 11 are removed and the disk is applied over the supporting element 12.

In this way the supporting pad may be quickly and conveniently adapted for use with any one of a series of selected-disk sizes, and while the supporting element is of less thickness and resistance as its size is decreased by the removal of the larger disks, this decrease in resistance makes very little difference 'as the necessity for support decreases with the size 01' the disk and with the amount which the disk overhangs the central supporting hub 1.

My supporting pad is particularly intended for such operations as are shown in Fig. 7, in which a disk 25 is supported by the two elements 11 and 12 of the supporting pad and is employed against a concave surface 26. The outer edge only of the disk is in effective operation and the nature of the supporting pad is such that this edge can be used to enter sharply concave recesses, such as are shown between a panel 2'7 proper anda bead strip 28.

The present pad may also be used for supporting abrasive disks in the more common operations, such as surfacing flat panels, where a considerable area of the disk engages the panel and I have found that the separable supporting elements, it formed 01' a tough resistant material, are an entirely adequate support for disks for most of their operations, are relatively inexpensive and have a relatively long life.

It will be understood that while I have shown special engaging means for maintaining the separable parts of the supporting pad and the disk in operative relation, other means may be employed for this purpose, such for example as a standard flat headed screw which is employed in most machines of this character for clamping the surfacing disk against the supporting pad.

Other modes of applying the principle of my invention may be employed instead of the one explained, change being made as regards the structure herein disclosed, provided the means stated by the following claim or the equivalent of such stated means be employed.

I therefore particularly point out and distinctly claim as my invention:-

A supporting element of the character described comprising a rigid hub provided with oppositely directed circumlerentially extending locking wings on one surface, a series of stepped sepa- 

